1. Field of the Invention
The invention relates to a new leather manufacturing process which gives an enhanced natural feel to automotive leather without sacrificing wear, abrasion-resistance, adhesion or other qualities essential to satisfying rigorous automotive leather specifications.
2. Description of Related Art
Leather manufacturing is a technology which has developed over many centuries using cattle, goat, kid, sheep and lamb hides, and even horse, pig, kangaroo, deer, reptile, seal and walrus, among others. The properties of the leather end-product vary depending upon the type of hide as well as the method used to tan and otherwise to treat and to finish the hide used to make it. Leather production normally consists of three processes, namely, the “beamhouse” processing; tanning; and finishing. The “beamhouse” process removes dirt and unwanted constituents of the hide, such as hair. Tanning includes the physical and chemical processes whereby the collagen of the leather is crosslinked to stabilize the leather into a permanent material which will not putrefy and decompose. Finishing gives the leather the properties essential for its ultimate use.
Leather is used in an enormous variety of applications, including but not limited to furniture upholstery, clothing, shoes including athletic shoes, luggage, handbag and accessories and automotive applications, including automotive seating, and instrument panels, door panels and other interior components. Of all the uses of leather, virtually the most difficult durability specifications to meet are those in the automotive industry, because the life of the leather must be extremely long in the automotive application while at the same time the leather must be able to withstand excesses of physical stress, temperature extremes and sunlight. Traditionally, therefore, automotive leather has required intensive manufacturing treatment, usually with repeated polymer coatings during the finishing process, in order to meet the applicable strength and durability standards.
Unfortunately, the traditional addition of heavy polymer coatings to the surface of the leather has also altered the natural hand and feel of the leather, so that the most durable leathers for automotive applications heretofore also had the poorest aesthetic qualities. Ironically, these traditional, heavily coated leathers often resembled, to the discerning touch, the very vinyl or other leather-substitute materials for which satisfactory natural leather replacements were sought. Reducing the number of polymer coatings and/or the amounts of polymer applied per layer can restore natural feel to the leather but then in turn reduces wear-resistance and other strength properties. In view of the aesthetic reasons for incorporating leather into automotive interiors in the first place, rendering the leather into a seemingly polymeric product is counterproductive. Therefore, a need remains for a leather manufacturing method which can meet strict automotive standards and still retain the hand and feel characteristics of “natural” leather such as aniline and semi-aniline leather; leather types which heretofore have not had sufficient light and stain resistance to be used in automotive applications.